A three metre liquid hydrogen target

An apparatus with a 3 m liquid hydrogen target is described which was designed to study the production of K mesons with the Serpukhov accelerator. Apart from the target the apparatus consists of a simulator for background measurements, a forevacuum pump, the gas control system, and siphons and dewars required to prepare the target for operation and to supply the liquid hydrogen and nitrogen. The target consists of an inner cylindrical vessel for liquid hydrogen, around which is the annular liquid nitrogen vessel to reduce the heat influx. The hydrogen and nitrogen vessels are inside a demountable vacuum jacket. Control of operation of the target is discussed, and various emergency conditions are considered.